Hydrocarbons can be produced through a wellbore traversing a subterranean formation. In some cases, the formation may be unconsolidated or loosely consolidated. Particulate materials, such as sand, from these types of formations may be produced together with the hydrocarbons. Production of particulate materials presents numerous problems. Examples of problems include particulate materials being produced at the surface, causing abrasive wear to components within a production assembly, partially or fully clogging a production interval, and causing damage to production assemblies by collapsing onto part or all of the production assemblies.
Gravel packing the well adjacent to the production interval can assist in stabilizing the formation surrounding the production interval and in filtering particulate materials before the particulate materials enter the production pipe. Gravel packing can include lowering a sand control screen into the wellbore on a work string to a position proximate a selected production interval. A fluid slurry, including a liquid carrier and a material such as gravel, is pumped down the work string and into the well annulus formed between the sand control screen and a perforated well casing or open hole production zone. The gravel is deposited in the well annulus to form a gravel pack. The gravel pack is highly permeable to hydrocarbon fluids, but can block particulate material carried in the hydrocarbon fluids. The gravel pack and sand control screen can also stabilize the formation surrounding the production interval to prevent formation collapses.
Complete gravel packing at a selected production interval can be difficult to achieve due to the formation of sand bridges and other complications experienced when pumping the fluid slurry down the work string. Expandable sand control screens can be used in place of gravel packs that may be less problematic to locate in the wellbore and may provide similar filtering and formation stability as gravel packs.
One expandable sand control screen is a control screen assembly that includes a swellable material, such as a high-swelling rubber, and a filter device on the exterior of the swellable material. The swellable material can be located proximate the production interval and, when activated by a fluid, expand to displace the filter device to the wellbore. The assembly includes openings through which hydrocarbon fluids are directed by the filter device into a base pipe. A telescoping piston can be located in the opening and can support the filter device as the swellable material expands. This type of expandable sand control screen can be effective in filtering and providing formation stability.
In some applications, however, the swellable material may swell into the openings or otherwise swell to block, partially or completely, fluid communication between the interior and exterior of a base pipe. Blocking fluid communication may result in the swellable material partially or completely plugging the opening to the base pipe. A rework of the control screen assembly may be required to alleviate the plugging. Reworks cost substantial time and money because they require suspension of hydrocarbon production for a measurable amount of time and require duplication of work in locating the control screen assembly in the wellbore.
Therefore, screen assemblies that can provide radial support to formations and reduce or eliminate plugging are desirable. Screen assemblies that eliminate or reduce reworks are desirable.